1. Field of the Invention
The present invention relates to a clamping device and more particularly to a clamping device for securely clamping two framing members together to facilitate their joining.
2. Description of the Prior Art
In construction there is frequently a need for fastening a series of vertical studs between two horizontally-extending plates. This type of construction has dramatically changed in recent years in that modular units are used for sheathing and finish panel require stud alignment to be exact. Sheathing has changed from wood boards to plywood, to fiberboard and now to insulating foam boards which have no structural integrity. These changes have created the need to develop new tools and procedures that provide the code required strengths.
The known procedure for fastening a vertical stud between two plates is by simply holding the stud in position and toe-nailing it to the plate using angularly driven nails. However, the driving of the nail into the stud causes both horizontal and vertical movement, therefore causing misalignment and destruction of the wood fibers that surround the nails.
Although several devices have been proposed for clamping the stud relative to the plate for the purpose of nailing, they are often only partly effective, limited in use, require a second person for their use, and demand a prohibitive amount of time.
Work holding devices for temporarily holding structural members, such as structural wood framing members used in residental construction, in a desired fixed relationship to facilitate their assembly are well known, although their use has heretofore been confined to rather limited situations. For example, structural framing holding fixtures are regularly used in factories and the like to assembly entire wall sections for use as prefabricated structural modules. However, as a result of the size and width of these fixtures, their use has not been extended to framing assembly on the job site.
In addition, on-site assembly of structural framing members presented problems of a different type than those which are usually encountered in factory jig-assembled structures. For example, temporary or permanent framing members may be required to complete or support a partially completed structure. Generally, the member to be added is manually held in place within the existing structure and nailed or otherwise fastened in place. In some instances C clamps or the like have been employed as temporary connecting fixtures. However, in either case the added member can be easily misaligned or moved by the reaction force caused by nailing, etc. This movement caused by the hammering forces may result in misalignment of the framing members, which in turn results in out-of-square, misjoined sheathing, insulating, or finish paneling, warpage of finish surfaces, etc. Additionally, the movement (horizontal movement or misalignment and vertical movement or reaction bounce) results in the natural nail retention properties of the wood and fails to achieve the structural potential of the joined framing members.
Although portable clamping fixtures have been proposed, their use has not found widespread acceptance. Some of these devices cannot be operated by a single workman or cannot accommodate differently sized structural members, or interface with the parts of the members to be joined. Other prior art devices contribute to the misalignment of the structural members by their own non-concentric weight, or are of such a size that they cannot be easily handled and transported, such as in a tool box, or are unduly complicated. It has been shown that any of these factors will discourage even the most conscientious workman from using the work holding device, even if available at the job site.
In new building construction, modular-type walls may be prefabricated with each connection made by nailing through the toe or head plate, as the case may be, into the end grains of the stud. In such construction, the end grain nailing generally has little or no structural value and relies exclusively upon the structural properties of the sheathing for the strength of the joined framing members. However, in all other perpendicularly framed construction where access is limited to one side of the framing members, toe-nailing is used. It has been said that quality toe-nailing is an art because few achieve efficiency, accuracy and structural integrity at the same time. In traditional toe-nailing, a framing stud is held in place by the workman's foot or knee at a position slightly removed from the intended position of the stud, and a first nail driven nearly vertically to join the stud and plate. Thereafter, a second nail is driven at a greater angle, which causes the stud to move to its intended position. These first two nails have little structural integrity, and act only to hold the stud in the position for subsequent nailing operations. Although subsequent nails are needed excessive or careless use of such nails may tend to splinter one or more of the structural members, reducing the strength of the connection.